Colloquium: What can a bloom date tell us about climate change?
Dr. Jonathan Auerbach will present his talk “What can a bloom date tell us about climate change?” virtually at 11AM on Zoom on March 18, 2025.
Abstract: The law of the flowering plants states that a plant blooms after being exposed to a predetermined quantity of heat. The law is among the oldest statistical discoveries still in use today, stated by Réaumur in the eighteenth century, popularized by Quetelet in the nineteenth century, and used to reconstruct historic temperatures and study climate change in the twentieth and twenty-first centuries. But a recent body of literature has called into question whether bloom dates are in fact a reliable measure of historic temperatures.
In this talk, I will reexamine the law of the flowering plants using results from renewal theory. I will first challenge evidence suggesting that bloom dates are not a reliable measure of historic temperatures. I will then show that popular methods for temperature reconstruction likely overestimate the difference between past climates and the climates of today. Finally, I will conclude by presenting a model for reconstructing temperatures from bloom dates.
Jonathan Auerbach is an assistant professor in the Department of Statistics at George Mason University. His research covers a wide range of topics at the intersection of statistics and public policy. He has broad methodological interests in the analysis of longitudinal data, particularly for data science and causal inference. His policy interests include urban analytics, open data, and the collection, evaluation, and communication of official statistics. Auerbach is the 2024-2025 president of the Washington Statistical Society and previously served as the 2020-2021 science policy fellow of the American Statistical Association. He is part of a joint project between the American Statistical Association and George Mason University monitoring the health of the federal statistical system.
For Zoom meeting information please contact Dr. Sarah Lotspeich at lotspes@wfu.edu